Expansion joint



Jan. 7, 1941. D. E. WILLARD EXPANSION JOINT Original Filed Oct. 9, 19335 Sheets-Sheet l ZowaM Jan. 7, 19411. 2 D, "E, WILLAR 2,227,614

EXPANS ION JOINT Original Filed 00139, 1935 5 Sheets-Sheet 2 Jan. 7,1941. D. E. WILLARD EXPANSION JOINT Original Fild Oct. 9, 1955 5Sheets-Sheet :5

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Jan. 7, 1941. D. E. WILLARD EXPANSION JOINT Original Filed Oct. 9, 19335 Sheets Sheet 4 Jail. 7, 1941.

D. E. WILLARD EXPANSION JOINT Original Filed Oct. 9, 1935 w III/ll Innr5 Sheets-Sheet 5 atented Jan. 7, 1941 PATENT OFFICE 2,221,,e14 EXPANSIONJOINT Donald E. Willard, lDanville, Ill,

Application October 9, 1933, aerial No. 692,735

Renewed. November Iii, 193i! '15 illaims. ioi. ail-it) My inventionrelates to expansion joints for roadways, pavements, concrete slabs,wall sections and similarstructures where it is desired to provide ayielding filler of some kind between t adjoining sections that willenable the latter to expand and contract under temperature changeswithout buckling or cracking, and is concerned more particularly withdevising a chair or support for a simple strip having yielding andexpansion W characteristics which can be positioned at the time oflaying a roadway, for example, and forms a permanent part thereof.

A common type of expansion joint now employed in the building ofroadways. for example, m takes the form of a simple bituminouscomposition strip,.or a sponge wood strip, or some type of compressiblematerial. In building roadways equipped with strips of these types,wooden planks are located transversely of the road in 2i) the positionsto be subsequently occupied by the expansion strips and the concrete ispoured into the spaces between pairs of the planks. After the concretehas hardenedfthe planks are removed, the expansion strips are driveninto the 25 cavities between adjacent, sections, and a substance, such'as pitch and the like, is poured along the cracks above the strips.

The foregoing practice' is attended with many disadvantages, such as theuse and cost of the 30 temporary dividing planks between adjoining slabsections, the necessity for withdrawing these planks after the concretehas hardened, and the subsequent inserting of the expansion strips.

It is therefore one object of my invention to 35 devise an expansionjoint which eliminates the use of temporary planks, which can be locatedwith accuracy in advance of pouring the concrete, and which terms apermanent part of the roadway, or other structural condition. y

40 A further object is to devise a joint of the character indicatedwhich is additionally adapted to prevent relative vertical shifting ofadjoining slab sections, which is further provided with parts whichinterlock with the concrete, and which may 45 be arranged to supportreentorcing members that are embedded in the slabs.

A further object is to provide a pair of supports for a simple stripmember having expansion characteristics which can be positioned by 50the usual ground locating stakes prior to pouring of the concrete, whichhas suflicient strength to withstand the heavy impacto! the pouredconcrete, and which, because of its fabricated construction, can be madefrom rolled steel strips 55 that are punched and bent into .deiiniteshape no provision is and secured by welding, riveting, or otherdesirable fastening means.

These and other objects of my invention will be set forth in thefollowing specification, reierence being had to the accompanyingdrawings, and the novel means by which said objects are eiiectuated willbe definitely pointed out in the claims.

In the drawings:

Figure 1 is a perspective view of the improved chair or support utilizedfor the positioning of the expansion strip.

Fig. 2 shows amodified type of chair in which made for the support ofreenforcing bars which resist relative vertical shifting of adjoiningslab sections.

Fig. 3 is a perspective view of the expansion strip.

Fig. 4 is an elevation, partly in section, of the type of chair shown inFig. 1, showing the expansion strip in position and the mounting of thereenforcing bar which extends between adjoining slab sections.

Figs. 5 and 6 are sections along the lines 5--5 and 6-45, respectively,in Fig. 4, looking in the direction of the arrows.

Figs. '7 to 9,'inolusive, are perspective views, partly in section, ofthe central portion of my improved chair, showing the expansion strip inposition and the association therewith of a strip for covering the upperedge of the expansion strip and other partstor facilitating bonding ofthe chair with the concrete. Fig.8 additionally shows the manner inwhich the chair may be utilized to support, in conjunction with anadjoining chair, a reeniorcing grid which is embedded in the concrete ofthe associated slab section.

Fig. 10 is a vertical section showing a still further modification ofparts which may be associated with the chair to improve its bond withthe concrete of adjoining slab sections.

Figs. 11 and 12 are plan views of the construction shown in Fig. 10,Fig. 12differing from Fig.

11 in that a. portion of the offset reenforcing member is eliminated.4.)

' Fig 13 isa plan view of a roadway, partly in section, showing myimprovedexpansion joints in position and a suggested arrangement foralternatively reversing the positions of the chairs on opposite sides ofthe expansion strips across the width of the roadway. r

Fig. 14 is a section along the line I l-i4 in Fig. 13, looking in thedirection of the arrows.

Fig. 15 is aperspective view showing the use of a temporary cover stripin connection with my improved chair to protect the upper edge .of theexpansion strip against the hazards of the roadway laying operation.

Fig. 16 is an elevation as modified for use with obtaining at theshoulders.

Fig. 17 is a section along the line |1 l1 in Fig. 16, looking in thedirection of the arrows.

For the purpose of illustration and as exemplifying one use of myexpansion joint and the suptween.

Referring to Figs. 1 to 6, inclusive, the numeral I 0 designates myimproved chair which comprises a footing strip H, from the centralportion of One or the uprights i2 is provided with a keyhole slot I1 andboth' of the uprights are provided with elongated slots I 8 which arepositioned above the slot l1. l9 projects upwardly from and adJacentthat H nearest to upright I9 is flanged as at 20 for securement to thestrip I I. The upper end of the upright I9 is identical with the uprightIS in that it is provided but isprefer apertures 26 may be located alongthe footing strip II when the chair is positioned prior to laying or theroadway.

In Fig. 3 is illustrated the preferred form of expansion strip 21 whichis composed of a pair of strips 28 that ting relation.

in order to receive ground locating stakes I Fig. 4 that,

- sion strip half of the total cross-sectional area of the strip. Withthis arrangement, the strip can be comof suitable apertures 3| may beappropriately dis- 5 posed through both strips 28 to receive thereenforcing bars hereinafter explained. The exuse of structures thestrip may be varied as desired and may be as low as one-half In Fig. 4is illustrated a characteristic employment of my improved chair inadjacent portion or the bar 31 by reason of the 75 sleeve 34.Accordingly, as the two slab sections move toward and away from eachother due to temperature changes, the reenforcing bar will slip easilywithin the sleeve 34, so that this con- 5 'struction aifords a simplearrangement for preventing any relative vertical shifting of the slabsections, ,while freely permitting their movement toward and away fromeach other.

In moving toward the left, from the position l shown in Fig. 4', the bar31 shears off the flange it whose only function is to limit the initialinsertion of the bar in the sleeve in order to leave space for thesubsequent movement of the bar to the left of the flange. la In order toprovide a strong interlock with the concrete in the adjoining slabsections, reenforce the structural strength of the joint, or to act as asupport for reenforcing members which are subsequently embedded int 1econcrete of the ad-. 20 joining slab sections, the assembly shown inFig. i is preferably associated with other parts which are moreparticularly illustrated in Figs. '7 to 12, inclusive.

Referring to Fig. 7 which shows the chair con- 25 struction in theregion of a joint, 2. cover strip 39 having an inverted channel sectionencases that portion of the expansion strip above the upright bentportions H, the web portion 40 of this cover strip being slightly spacedabove the top side of 39 the expansion strip and the central portion ofthis web is deflected transversely towards the expansion strip andlongitudinally of the cover strip to provide a web member that willreadily yield under the expansive forces of the concrete. The tit sidesof the cover strip extend downwardly along the sides of the expansionstrip and are then bent laterally as at 4| and then bent upwardly toform the flanges 42. This cover strip is applied when the assembly hasthe appearance shown in Fig. l lid and the strip is pressed downwardlyon the ex.-

pansion strip with thefianges 42 located within and in abutting relationto the flanges l5. The liangesl and 42 are then bent or curled inwardlytoward the expansion strip, as generally indirid cated by the numeral43, thus firmly locating the cover strip in position. It will beunderstood that the cover strip 39 extends between at least a pair ofchairs it) along the roadway, and may extend across the full width ofthe road.

W In Fig. 8 is shown a still further. modification of the chairconstruction employing the cover strip 39. In this modification, afterthe cover strip is placed in position, but before bending the flanges l5and 42 together, a reenforcing bar or td wire 44 is laid along the coverstrip flange 4 l, and

this reenforcing bar forms one side of a reenforcing grid 45 composed ofa number of bars or wires t4 disposed in parallel relation and whichrest upon and are supported by a number to of wires-.46. The cover stripflange 42 may be slotted in suitable locations, as at 41, in order topermit the bending of the ends of the wire 46 around the reenforcing bar44. It will be under stood that Fig. 8 shows the-chair supporting on p5opposite sides thereof the ends of a pair of reenforcing grids 45 andthat similar chairs support the opposite ends of the same-grids. Afterthe reenforclng bars 44 have been positioned as noted above, the flangesl5 and 42 are curled over run the length of the expansion strip whichforms the side of a wire grid or mesh 48; which is looped around thebottom of the strip. Intermediate wires which run parallel to the stripmay be supported in bends 49 which are offset from the up- 5 rights W.This mesh serves to stiffen the strip against sidewise deflection andalso insures an adequate bond with the concrete.

In Figs. to 12, inclusive, a slightly modified form of covering strip 5|is employed. This 10 strip is likewise provided with laterallyextending, support flanges 52 and vertically extending flanges 53,corresponding to the flanges 4| and 42, respectively. The former flangesare periodically notched as at 54.. Resting on the support flanges 52are the wires 55 of a reenforeing member 56 and connecting these wiresare other wires 51 which are preferably offset laterally from the sidesof the expansion strip so that they will be embedded in the concrete ofthe adjoining slab section. As with the other modifications, the flangestit and i5 are curled over to hold the reenforcing member it inposition. Fig. 10 shows the relation of the expansion joint to theadjacent slab sections of a roadway.. The cover $5 strip is depressedslightly below the surface of the road, preferably at least one quarterof an inch. With this construction it is unnecessary to cover the stripwith pitch, so that the road surface is free from objectionable bumps.The modification shown in Fig. 12 differs from that shown in Fig. 11only in a slight change made in the reenforcing member. Instead ofemploying a continuous offset wire till, the intermediate portionthereof is removed as at 58, so that the reenforcing member 59 iscomposed of a plurality of individual wires having a substantiallyU-s'hape appearance, as shown in Fig. 12.

In. Figs. 13 and 14 is shown a suggested method of arranging my improvedchairs and the accompanying expansion strips in a roadway. These chairspreferably extend lengthwise of the roadway and are disposed inparallel, spaced relation across the width-thereof.

In positioning these chairs, they are preferably located by simpleground stakes 60 which enable the chairs to be located with greataccuracy. The expansion strip ill may be placed in the chairs eitherbefore or after the latter have been located on the ground and any oneof the before described modifications may be employed in connectiontherewith, dependent upon the nature of the roadway. Whichever of themodifications, as illustrated in Figs. '7 to 12, inelusive, is adopted,it will be apparent that the chairs will rigidly hold the expansionstrips in position against the pouring impact of the concrete and that,after the concrete has hardened, the roadway is substantially completed,since it is unnecessary to remove any part of the chair thereafter. Thelatter becomes a permanent part ofthe roadway and it provides a veryefficient means for locating the expansion joint from the verycommencement of road building operation. The relation of the height ofthe chair to the thickness of the roadway bed is preferably such thatthe web of the cover strip is substantially flush with, or a shortdistance below, the surface of the roadway. This strip thereforeprotects the expansion strip against wear and it is preferably composedof a material that will resist corrosion.

As indicated in Fig. 13, the chairs are preferably located transverselyof the roadway with the sleeves 34 located in alternating relation onopposite sides of the expansion strip. If the reenforcing grid member,as illustrated in Fig. 8, is employed, it will be obvious that thismember will extend between adjacent pairs of the chairs across the widthof the roadway, each grid member being supported 'by the adjacent pairsof chairs.

Under, certain conditions, it is contemplated that the nature of theroadway or the pavement may be such, considering the weight of'trafiiccarried, that it may be possible to eliminate any necessity for thereenforcing bars 31. Under these conditions, a chair 6|, as illustratedmore particularlyin Fig. 2, may be used. This chair is substantiallyidentical with chair I0, except that the footing strip 62 is somewhatshortened and the end uprights are eliminated.

.In Fig. 15 is illustrated a method of protecting the upper edge of theexpansion strip against the hazards of the road laying operation. Thesestrips are rather easily damaged and it is important to provide somemeans for protecting its upper edge, whether or not the cover strip 39is employed.

Fig. 15 shows a. portion of the chair in the condition as illustrated inFig. 4, it being assumed that the joint is not being associated with anyform of bond-forming agency. Under these conditions, a temporary channelstrip 62 is placed in inverted position along the upper edge of theexpansion strip, the distance between the flanges of this channel beingsuflicient to also include a cover strip 39, if the latter is employed.The channel 62 is held in position by looping wire 63 therearound andunder the flanges M. The concrete is then poured on opposite sides ofthe expansion joint and just before the concrete is in condition forfinishing, the wires are cut and the temporary channel 62 is removed. Itwill be understood that this channel will have sufficient strength toeffectively protect the expansion strip proper from being damaged by thebucket which delivers the concrete, or the boom which carries thebucket, in the event that either of these parts are rested on or come incontact with the strip.

In- Figs. 16 and 17 is illustrated atfurther modification of my improvedexpansion joint which is intended for use in connection with that typeof roadway which is provided with a greater thickness along theshoulders thereof than in the center of the road. Under theseconditions, it is obvious that some form of expansion strip must beprovided at the portions of increased thickness. This requirementcan beadequately met without requiring any special shape of expansion strip,except to the extent presently noted.

Referring to Fig. '16, the numeral 64 designates a chair having uprightswhose length is suitable for the cross-sectional width of the center ofthe road and other chairs 65 whose uprights are somewhat longer andwhich are intended to be placed adjacent the outer edges of of theroadway. Along the shoulders or edges of the road, the additional slabthickness is pro vided for by a substantially sector-shaped piece ofexpansion strip 61 which is placed under the outer ends of the principalexpansion strip. A wire mesh or grid 68 is supported by the chairs inthe manner generally indicated in Fig. 9 and is looped around the loweredges of the strips, including the piece 61. To permit this action,certain of the vertical wires of the mesh are cut, as indicated at 69,so that the intermediate portions of the same wires may be shiftedsufficiently to accommodate the increased width of expansion strip.

I claim:

1. An expansion joint for concrete roadway construction adapted forlocating in advance of pouring the concrete comprising a yieldable stripfor positioning between adjacent slab sections, footing strip meansresting on the supporting surface for the roadway, a pair of spaceduprights carried by the footing strip means and engaging the oppositesides of the yieldable strip to maintain the same against the pouringimpact of the concrete when the slab sections are laid, a sleeveextending laterally from one upright,

a reenforcing bar slidable in the sleeve and extending through theyieldable strip for inclusion within the adjacent slab section,and-uprights carried by the footing strip means remote from theyieldable strip for supporting the ends of the sleeve andvbar,respectively! 2. An expansion joint for concrete roadway constructionadapted for locating in advance of pouring the concrete comprising ayieldable strip for positioning between adjacent slab sections, footingstrip means resting on the supporting surface for the roadway, a pair ofspaced uprights carried by the footing strip means and engaging theopposite sides of the yieldable strip to maintain the same against thepouring impact of the concrtee when the slab sections are laid, a sleeveextending laterally from one upright, a reenforcing bar slidable in thesleeve and extending through the yieldable strip for inclusionwithin theadjacent slab section, and uprights carried by the footing strip meansremote from the yieldable strip for supporting the ends of the sleeveand bar, respectively, and having parts bent around the sleeve and barto maintain the same against movement by the concrete.

3. An expansion joint for concrete roadway construction adaptedforlocating in advance of pouring the concrete comprising a yieldablestrip for positioning between adjacent slab sections,

footing strip means resting on the supporting surface for the roadway, apair of spaced uprights secured to the footing strip means and engagingthe opposite sides of the yieldable strip to maintain the same againstthe pouring impact of the concrete when the slab sections are laid, theupper ends of the uprights being outwardly flanged, and a reenforcingmember supported by the flanges for embedding in the concrete.

4. An expansion joint for concrete roadway construction adapted forlocating in. advance of pouring the concrete comprising a yieldablestrip for positioning between adjacent slab sections, footing stripmeans resting on the supporting surface for the roadway, a pair ofspaced uprights carried by the footing strip means and engaging theOpposite sides of the yieldable strip to maintain the same against thepouring impact of the concrete when the slab sections are laid, theupper ends of the uprights being out- 1 till wardly flanged, a coveringpart extending along the upper edge and downwardly along the sides ofthe yieldable strip, the lower edges of the covering part beingoutwardly flanged in abutting relation to the'fianges on the uprights,and a reenforcing member supported by the flanges for embedding in theconcrete, said flanges bein bent around the reenforcing member,

5. In roadway construction, the combination of a plurality of expansionjoints spaced along the roadway and adapted for locating in advance ofpouring the concrete, each joint comprising a yieldable strip forpositioning between adjacent slab sections, footing strip means restingon the supporting surface for the roadway, a pair of spaced uprightssecured to the footing strip means and engaging the opposite sides ofthe yieldable strip to maintain the same against the pouring impact ofthe concrete when the slab sections are laid, and reenforcing means forembedding in the concrete carried by the uprights of and extendingbetween adjacent pairs of joints.

6. In roadway construction, thecombination of a plurality of expansionjoints spaced along the roadway and adapted'for locating in advance ofpouring the concrete, each joint comprising a yieldable strip forpositioning between adjacent slab sections, means engaging the strips tomaintain the same against the pouring impact of the concrete when theslab sections are laid, and reenforcing means for embedding in theconcrete supported by an adjacent pair of said means and extendingbetween adjacent pairs of joints.

7. An expansion joint for concrete roadway construction adapted forlocating in advance of pouring the concrete comprising a yieldable stripfor positioning between adjacent slab sections and adapted tosubstantially filll the space therebetween toaccommodate expansion ofthe slab sections, footing strip means resting on the supporting surfacefor the roadway, a pair of spaced uprights carried by the footing stripmeans and engaging the opposite sides of the yieldable strip to maintainthe same against the pouring impact of the concrete when the slabsections are laid, a sleeve extending laterally from one upright, areenforcing bar slidable in the sleeve and extending through theyieldable strip for inclusion within the adjacent slab section, and anupright carried by the footing strip means remote from one of the spaceduprights-for supporting the end of the sleeve.

8. An expansion joint for concrete roadway construction adapted forlocating in advance of pouring the concrete comprising a yieldable stripfor positioning between adjacent slab sections, footing strip meansresting on, the supporting surface for the roadway, a pair of spaceduprights carried by the footing strip means and engaging the oppositesides of the yieldable strip to maintain the same against the pouringimpact of the concrete when the slab sections are laid, a sleeveextending laterally from one upright a reenforcing bar slidable in thesleeve and extending through the yieldable strip for inclusion withinthe adjacent slab section, a frangible stop extending into the sleeveadjacent the end thereof remote from the spaced uprights and adapted toengage the end of the reenforcing bar to limit the initialinsertion'thereof, and an upright carstrip for positioning between slabsections and adapted to substantially fill the space therebe-" tween toaccommodate expansion of the slab sections, footingstrip means restingon thesupporting surface of the roadway, a pair of spaced uprightscarried by the footing strip means and engaging the opposite sides ofthe yieldab-le strip to maintain the same against the pouring impact ofthe concrete when the slab sections are laid, a sleeve extendinglaterally from one upright, a reenforcing bar slidable in the sleeve andextending through the yieldable strip for inclusion within the adjacentslab section, an upright carried by the footing strip means remote fromone of the spaced uprights for supporting the end of the sleeve, and afrangible stop carried by the last named upright and extending into thesleeve adjacent said remote end thereof to engage the end of thereenforcing bar to limit the initial insertion thereof.

10. In roadway construction, the combination of a plurality of expansionjoints spaced along the roadway and adapted for locating in advance ofpouring the concrete, each joint comprising a yieldable strip forpositioning between adjacent slab sections, footing strip means restingon the supporting surface of the roadway, a pair of spaced uprightscarried by the footing strip means and engaging limited portions of theopposite sides of the yieldable strip to maintain the same against thepouring impact of the concrete when the slab sections are laid, theupper ends of the uprights being outwardly flanged, a covering partextending along the upper edge and downwardly along the sides of theyieldable strip, the lower edges of the covering part being outwardlyflanged in abutting relation to the flanges on the uprights, andreenforcing means supported by the flanges and extending betweenadjacent pairs of joints for embedding in the concrete.'

11. An expansion joint for a concrete roadway having a reduced thicknessbetween the shoulders thereof and adapted for locating in advance ofpouring the concrete, comprising a yieldable strip for positioningbetween adjacent slab sections and having a uniform width slightly lessthan the reduced thickness of the adjacent slabs, a yieldable strip partinsertable below and in alignment with each end of the yieldable strip,the yieldable strip and strip parts being adapted to substantially fillthe space between adjacent slab sections to accommodate expansionthereof, spaced footing strips resting on the supporting surface for theroadway across the width thereof, a pair of spaced uprights carried byeach of the footing strips and engaging limited portions of the oppositesides of the yieldable strip including the strip part to maintain thesame againstthe pouring impact of the concrete when the slab sectionsare laid, the upper ends of all of the uprights being outwardly flanged,and a reenforcing member supported by the flanges for.

embedding in the concrete.

12. In a structure for installing a joint in a pavement, the combinationof a compressible strip adapted to be placed along a. line of theproposed joint, plate means for holding the strip in place during apouring of pavement material, a dowel bar for limiting vertical movementof the pavement adjacent the joint, the plate means having a baseportion, and members extending outwardly from the plate means forSupporting the dowel bar.

13. In a structure for installing a joint in a pavement, a dowel bar forconnecting adjacent slabs of the pavement, plate means interposedbetween adjacent slabs of the pavement, means extending across the jointand supporting opposite portions of the dowel bar during a pouring ofthe pavement material, the plate means being apertured to receive thedowel bar substantially centrally thereof.

14. An, expansion joint for concrete roadway construction adapted forlocating in advance of pouring the concrete comprising a yieldablespacer for positioning between adjacent slab sections, footing stripmeans resting on the supporting surface for the roadway, a pair ofspaced uprights carried by the footing strip means and engaging theopposite sides of the yieldable spacer to maintain the same against thepouring impact of the concrete when the slab sections are laid, a sleeveextending laterally from one upright, a reenforcing bar slidable in thesleeve and extending through the yieldable spacer for inclusion withinthe adjacent slab section,and uprights carried by the footing stripmeans remote from the yieldable spacer for supporting the ends of thesleeve and bar, respectively.

15. A dowel joint construction for concrete road sections havingjuxtaposed faces in spaced relation comprising a pair of end supportsand a pair of intern ediate supports, the supports being adapted foralignment longitudinally of the roadway and having horizontally alignedopenings, a dowel socket member extending through the openings of oneend support and the adjacent intermediate support and having its outerextremity carried by said one end support, and a dowel in telescopic:engagement with the socket member and extending through the openings ofthe other supports and having its outer extremity carried by the otherend support, the supports, dowel and socket member being arranged forembedment in the concrete of adjacent sections.

DONALD E. WILLARD.

